It's not just for spiders anymore.
Silk threads woven by spiders could be used to make bulletproof vests
and support structures for growing cells, among other materials in the
future.

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Spider-Man isn't the only person with an interest in spider silk.
While Spidey uses the threads to zigzag from building to building, or to
snare a bad guy, scientists are investigating silk for different
reasons.

Spiders make many different kinds o

And though researchers have learned a lot about silk by investigating
spiders, insects such as caterpillars, ants and bees also have been
studied for the sticky stuff. Scientists are even trying to get silk
from animals such as goats. Now isn't that really amazing?

It turns out silk might be good for weaving a lot more than shirts
and ties. In the future, the silky fibre might be used to make
supertough bulletproof vests and light, but strong parachute cords. Silk
also might work well for delicate tasks inside the body. Researchers are
experimenting with using silk to support growing cells, the same way a
construction crew builds scaffolding (metal or wooden structures) around
a building to help keep everything in its place during construction.
Silk might be a good material to give growing cells something to hang on
to.

Scientists think silk would be useful for so many things because it
is both extremely strong and very elastic "it can be stretched a long
way without breaking. Most of today's strong, elastic fibers are made
from petroleum products and there are harsh chemicals in the recipes for
these fibers.

If scientists can figure out how natural silk-makers make their
threads, the harsh chemicals might not be needed. Spider silk is an
ideal material," says Randy Lewis of the University of Wyoming in
Laramie. "If you can mimic (imitate) it, you can eliminate an awful lot
of the problems you have with all the man-made fibers that are currently
available." Humans have been gathering silk not from spiders, but from
silkworms for hundreds of years. Silkworms aren't worms at all, they are
actually caterpillars, or the young, of the silk moth. When it's time
for a silkworm to turn into a moth, the caterpillar spins itself a
cocoon out of one very, very long silk fibre.

The thread from unravelling a single silkworm cocoon can be 600 to
900 meters long! That's more than two times the height of the Empire
State building! Long ago, people learned how to raise silkworms together
in farms. Silkworms don't mind being crowded together, as long as they
have food, like mulberry leaves. In addition to making a nice fabric for
scarves and sheets, silkworm silk is also used by doctors for stitching
up cuts. But silkworm silk has its problems. A silkworm covers its silk
in sticky glue that holds the cocoon together.

Sometimes humans have a bad allergic reaction to this glue. And
silkworms spin only one kind of silk. Spiders, on the other hand, don't
use a sticky glue. And spiders make many different kinds of silk. "We
love the silkworm," says David Kaplan of Tufts University in Medford,
Mass., who has been studying silk for many years.

"But spider silk is so diverse , we want to exploit that." Most
spiders like to be alone. When they are crowded in one place they
sometimes eat each other. This makes it hard to have a 'spider farm' for
collecting silk. So, scientists are studying how spiders make silk, with
the hope that the technique can be copied, perhaps even in other
animals.